1. Field of the Invention
This invention relates to a speaker system for a theatrical home sound system, THX and Dolby AC-3, and, more specifically, to a surround speaker satisfying two different kinds of sound systems; one is the THX which is a surround speaker having a dipolar acoustic radiation characteristic, and the other is Dolby AC-3 which is a surround speaker of a monopolar acoustic radiation characteristic.
2. Description of the Related Art
FIG. 1 illustrates the construction of a THX system having a feature of a dipolar acoustic radiation characteristic. FIG. 2 illustrates the construction of a Dolby AC-3 system of a monopolar acoustic radiation characteristic. Conventionally, as the surround speaker systems which are typical home theater sound systems, the THX and Dolby AC-3 systems commonly have three front speakers; that is, a left front speaker 1, a right front speaker 2, a center speaker 3, and a sub-woofer 4. However, they have different surround speaker forms as follows.
While the THX system basically has the surround speakers 5 and 6 having a left and right dipolar acoustic radiation characteristic, the Dolby AC-3 system has the general left and right surround speakers 8 and 9 thereby providing a monopolar acoustic radiation characteristic. The THX surround speaker is preferably set up at a height of 1.5 to 3 m, but the Dolby AC-3 surround speaker is preferably set up at a height of 60 to 80 cm like a general speaker. In FIGS. 1 and 2, the reference numeral 7 indicates a screen.
Since the surround speaker 5,6 of the THX system is placed at the side of an audience and radiates sound bilaterally, the audience hears indirect sound rather than direct sound. Alternately, the surround speaker 8,9 of the Dolby AC-3 system allows the audience to possibly hear the direct sound.
However, the conventional surround speakers of a THX surround system and Dolby AC-3 system have a problem in their interchangeability. While the front speakers have nothing to do with this problem, the surround speakers involve such a problem because they are different from each other. For example, the surround effect becomes unnatural in the case where a sound medium in which recording is performed by the Dolby AC-3 method is reproduced through the speaker of a THX sound system. To solve the above problem, both THX and Dolby AC-3 surround speakers should be used, or alternatively only the medium for one method should be used.